The finished block-out now needs some fine detail to improve its realism. An .obj will work fine in ZBrush, but can be slow when frequently jumping between the two pieces of software. The GoZ button can resolve this issue by directly sending the mesh between ZBrush and 3DS Max.

Detail is added in ZBrush using an iterative, layered approach. One common mistake is to subdivide the mesh several times and then start adding fine geometrical information right after import. Lower subdivision levels should always be used while confronting the fundamental shape. Only when the potential of a given subdivision level is exhausted, should a further subdivision be made. When it comes time to add stitching and cracks (with the relevant subdivision level applied), anything courser should have already been applied. This is very important and will impact massively on the final result. It is good practice to build creases using a layered approach, larger marks using lower subdivision levels, and smaller ones using higher subdivision levels. 

For this chair, the Inflat Brush was used on the bolsters and lumbar support. 

Here is an exaggerated example of what the Inflat brush can do. It is most effective at low subdivision levels. Along with this tool, exists a setting to globally inflate the mesh. Using this will give the impression of foam filler pushing outward on the upholstery from within. The central pads, in particular, make good use of this approach.   

The Dragrect option under the stroke setting can be very useful when creating folds and creases. Alphas can be created directly in ZBrush to use with the Dragrect stroke option.   

    

After the High Poly model is created, we duplicate and then decimate it to generate a more performant version for 3DS Max. The reason we do this is because 3DS Max will struggle with the multi-million polygon mesh we created in ZBrush. We still want to keep the high-poly mesh's geometrical form, but with more efficient topology - Decimation Master helps us do this.

Please note: in the screenshot below, the mesh contains almost 14,000,000 points; after decimation, it contains 17,000 points. That's three orders of magnitude less!

This is a much more manageable mesh and can be sent back to 3DS Max using the GoZ button found in the Tools category.

This stage involves creating a low-poly version of the seat which can be implemented into FSW.

We start the low-poly version at the seat's central section. Firstly, a Box primitive is created in scene. We create this Box in order to use Step Build and can delete it after creating our first quad. Under the Surface roll-out in the Freeform tab, there is a Draw on Selection option. This will glue any polygons we create to the seat, ensuring our low-poly mesh conforms to the curvature of our high-poly. LMB will create points and Shift Clicking will build geometry between the points.

When it comes to smoothing groups, the seat is pretty straight-forward due to its organic shape. By rule-of-thumb, if something has a hard-edge, it should have its own smoothing group. Any edges below 45 degree, may either have faces sharing a single smoothing group or use multiple groups depending upon context. Where ever a UV border exists, should be a split in smoothing groups, for example.

Here is an example of this principle in use. There are 3 separate smoothing groups, 2 with 90 degree angles, and 1 with multiple 30 degree angles.

Another study to demonstrate what happens when baking normal maps with incorrect smoothing groups is as follows. This should be used on areas of mesh greater than 45 degrees when trying to conserve polygons. If feasible, the edge can be Chamfered and put into the same smoothing group as its neighbours.

All of the examples below have been baked with a Cage, which is essential to creating artefact free normal maps. Without a Cage, the artist has no control over normal data is projected across meshes.

The cube looks pretty good overall. There are no artefacts on the edges. There is one issue however: because right-angled edges are lumped into one group, there is a strange, wobbly shading anomaly across the object.

This is similar to example 1. If we baked this one without a Cage, we wouldn't get artefacts as the UV's are on separate islands to each other. Again, the only issue is the strange shading anomaly caused by the single smoothing group. 

 

This example is the perfect balance of quality and efficiency. There are no shading issues, no artefacts, and no anomalous lines running along the edges. If polygons need to be conserved, this is definitely the best option.       

 

This cube achieves the best quality, but at 9 times the cost of example 4. This is an example of an important asset the player will see frequently and up-close. Most of the time, this level of quality is unnecessarily.

We shall mostly use examples 3 and 5 in this tutorial as the organic form lends to smaller angles between faces. However, given the intricacies of the chair, different sections of geometry will be split into separate UV islands, allowing efficient texture map packing, and minimal texel distortion.

This next stage is very important to achieving a good final result and needs to be done correctly. This is not only to maximise space, but to balance neat and organised UV layout against good texel distribution. 

A very important step at this stage is to find or create a numbered UV layout grid and load it into 3DS Max.  Alternatively, 3DS Max's built-in chequed pattern can be used.

We start by applying a planar projection to the entire mesh in order to generate some UV's. We then plan where to place UV borders by inspecting the seat's curvature. It's generally good practice to place seams in areas hidden from the player's view, or lacking prominence. It's also appropriate to place UV seams along an geometrical seams in the object being portrayed, such as along the seat's leather stitch-work.

After the planar projection is added to the seat, there is some pretty bad stretching across the entire object.  

The seams are selected and broken into separate UV islands by using the Break function.   

The islands are selected and relaxed by either edge angles or polygon angles depending upon the shape to ensure the best UV distribution across the texture map.   

This example shows the UV islands at their most relaxed point. This means the texture map will look best with minimal stretching or distortion. This is not always ideal though as there are some strange shapes that do not fit neatly together on the map, therefore compromising UV space.   

Where we can, it's best practice to straighten the edges, allowing UV's to be packed together better. It's preferable to tolerate slight distortion towards UV island edges by straightening their boundaries.

This method has to be balanced though. In the two examples, you can see this principle in practice. The squarer of the shapes have straightened UV island boundaries with minimal distortion. However, this wouldn't work for the back of the seat given the extreme stretching this would produce. There is no perfect solution so discretion should be exercised at all times. The checkered pattern in scene will immediately highlight any problem areas.

When packing UV's, it's important to use the maximum space available. The Packing tool helps scale UV islands correctly and can be used as a starting point. The numbered square texture should be uniform across the entire object. Finally these seats have to be packed into an existing interior map so figuring out the location and rotation was challenging.

Cages are not only essential for avoiding normal map projection artefacts, but also to ensure all information from the high-poly mesh is captured in a bake correctly and without distortion. We set up assets for baking with 4 meshes in total:

In order to generate the Cage mesh, we duplicate the low-polygon mesh, add a Push modifier, and increase the Push value until the entirety of the decimated HP mesh is encapsulated.  We can then fine tune the mesh by manipulating individual vertices. Using the Soft Selection tool can be useful on organic forms. The low-poly mesh and Cage are then exported to corresponding folders along with the high-poly, which is exported directly from ZBrush.

The meshes are loaded into xNormal, an export path is setup, and maps are generated. In terms of baking options, most things are left to default. For this 4069px x 4096px example, the Padding is set to 16, Bucket Size to 32, and Antialiasing to 4x. Renderer should use Default bucket renderer. We created 2 texture maps: a Normal Map and an Ambient Occlusion Map.

 

When setting up a new scene, we ensure the following settings are used.

The resolution is mutable, meaning it can be changed at any time. In other words, scaling is non-destructive.

FSW expects Albedo and Emissive maps to be Gamma-encoded, and all other maps to be in Linear-space (see: Map Formats). Care should be taken to ensure textures are setup accordingly in Substance Painter's TextureSet Settings window, and in any real-time engine used to preview the results.

As described in the Aircraft Livery Tutorial, the 2 textures created in xNormal (Normal Map and Ambient Occlusion Map) can be drag-and-dropped into the Project section of the Shelf. After they have been loaded into the appropriate slots of the TextureSet Settings, the remaining textures are baked. Another Ambient Occlusion Map can also be created here without loading any high poly meshes into the baker. This bake will highlight occluded areas more clearly and has other uses such as providing the basis for a dirt mask. Other items such as Curvature, Thickness, Position and WSN should be baked with the high-poly and Cage loaded into the Substance Baker. 

The final seat model is integrated into the master 3DS Max file and added to the LOD tree, ready for exporting to engine. Aircraft setup and export procedures are covered in the FSW Aircraft Primer section.